Thermostat housing Question.

[viking3099]

I was wondering if anyone knew what the little vacuum sensor does that is screwed into the back of the thermostat housing does, and has lines 3 and 12 running into it. I'm curious to see if a malfunction with this would cause problems with idling.

[Immeraufdemhund]

umm. I broke mine and it doesn't have any problems with idle. Does your check engine light come on? How long has it been since a new tune up? Normally that doesn't mess with your idle.

[AccordEpicenter]

i think its a vacuum thermoswitch but i cant remember what it does... its like some kinda wax valve

[McNick]

This is thermovalve of evaporation system. This valve open, when engine temp is above ~55 Celsium and allow manifold vacuum (line #12) open purge control valve ( by #3 line).

[viking3099]

Would a malfunction with this valve cause problems with idling. i.e. : Rolling idle, High idle...

[cruznz]

by-pass the thermo-valve and connect the 2 hoses together to see if theres a difference

[McNick]

... or block both hoses to see if theres a difference.

[BITESIZE]

It might cause high idling. I believe if you take off the egr valve hose the idling will go higher, so it could make a difference. You'd have to use a vacuum tester and see how much psi is going through the lines. good luck.

[McNick]

EGR (exhaust gas recirculation) is not the evaporation system. Last one control the flow of fuel tank gases to intake manifold.

[Shin87LXI]

Funny,

After a 3rd transmission install, I too broke this thermostat connector. Where can you buy a new one? 87 LX-I exclusive?